We propose to extend our studies in the whole animal on the action of ionizing radiation and drugs on nucleic acid metabolism in normal and neoplastic tissue. It is our goal to determine and, if possible, minimize the physiological perturbations which are operative in such experiments, so that we may better interpret such data. To supplement and improve our understanding of how radiation either alone or in combination with drugs influences our results, we intend to enlarge our program to include tissue culture experiments. It is our aim both in whole animals and cells in culture to relate the effect of radiation and drugs on nucleic acids and their associated membranes. It is hoped that such studies will lead to a better understanding of how radiation interferes with cell function and results in cell death.